Three-dimensional analysis of the change in the curvature of the smiling line following orthodontic treatment in incisor class II division 1 malocclusion

What does the Dentists Act say about orthodontic treatment choice?

Should one theory of dentistry be allowed to predominate over another in a profession that has a monopoly? This question is traced to the original Dentists Act of 1878, which was set up as a result of the dental reform movement which sought to prevent unqualified dentists from practising. A report into the 'extent and gravity of the evils connected with the practice of dentistry and dental surgery by persons not qualified under the Dentists Act' published in 1919 showed that the original Act had been unsuccessful in this respect, which led to the 1921 Act. The 1919 Report and the current Dentists Act of 1981 both refer to and support this contention. Can a licensed monopoly be justified in excluding the practice of expansion in non-extraction functional jaw orthopaedics while accepting conventional extraction orthodontics? This is especially so, as there is an expanding evidence base to support expansion in functional jaw orthopaedics.

Changes in facial expressions following functional orthopaedic treatment for Class II division 1 malocclusion: a prospective controlled study

OBJECTIVE

The aim of this study was to quantify changes in facial expressions in children with Class II division 1 malocclusion treated with functional appliances.

MATERIALS AND METHODS

A prospective controlled study was carried out evaluating 20 children with Class II division 1 malocclusion (ages 9-13) treated with a functional appliance for 12 months (treatment group). Age- and gender-matched children without immediate orthodontic treatment need were followed up without treatment for 12 months (control group). A frame-mode video sequence was taken of each subject at the beginning and end of the 12-month study period, during which 5 distinct facial expressions (posed smile, spontaneous smile, aggressive smile, lip pucker, and maximal mouth opening) were recorded. Frames at which each facial expression was at its peak were analysed. Changes in horizontal and vertical facial anthropometric distances brought about by performing each facial expression were measured. Intragroup differences following treatment were assessed using paired t-tests, whereas intergroup differences were assessed using unpaired t-tests.

RESULTS

All treated children showed an improvement in dentoalveolar relationships. Initial facial expressions differed between groups, with the treatment group showing less marked changes during lip pucker and more marked changes during maximal mouth opening. In contrast, no statistically significant differences were found between groups for the final facial expressions.

CONCLUSIONS

This study suggests that functional appliance use in growing children with Class II division 1 malocclusion tends to normalize soft-tissue movements during facial expressions.

Clinical effectiveness of orthodontic treatment on smile esthetics: a systematic review

Objectives: The aim of this systematic review is to identify how different types of orthodontic interventions affect the esthetics of the smile, any time after orthodontic treatment.

Materials and methods: A systematic search of the literature was carried out using 5 electronic databases (PubMed, Embase, The Cochrane Library, Scopus, Dentistry and Oral Sciences Source) that included articles until October 2017. Randomized and non-randomized controlled clinical trials, case–control observational studies, and cohort and cross-sectional studies with validated data collection and/or follow-up periods reporting on orthodontic interventions that changed the smile any time after orthodontic treatment were part of the study protocol. Only studies that were published in the English language and those that had human patients of any age and gender who underwent orthodontic treatment were included.

Results: A total of 814 articles were found and 9 of them were included (7 cohort and 2 cross-sectional studies). Among the selected articles, 8 stated the type of orthodontic intervention used during treatment and 1 did not specify the intervention. Eight articles were judged of moderate risk and 1 had high risk of bias.

Conclusion: Orthodontic treatment affects the esthetics of the smile in three dimensions. There was slight evidence that extractions do not affect the smile width and buccal corridors area. Evidence on palatal expansion was controversial. The remaining existing data evidence that investigated smile esthetics after orthodontic treatment was uncertain. Therefore, more validated, evidence-based studies are needed.

Superimposition of 3D digital models: A case report

INTRODUCTION

Superimposition of digital models may be performed to assess tooth movement in three dimensions. Detailed analysis of changes in tooth position after treatment may be achieved by this method.

AIM

This article describes the method of superimposing digital models with a clinical case. It emphasizes the difficult procedure of superimposing 3D models in the lower arch. A methodology for superimposing mandibular models acquired with a structured light 3D scanner is discussed.

CONCLUSION

Superimposition of digital models is useful to analyse tooth movement in the three planes of space, presenting advantages over the method of cephalogram superimposition. It seems feasible to superimpose digital models in the lower arch in patients without growth by using a coordinate system based on the palatal rugae and occlusion. The described method aims to advance the difficult procedure of superimposing digital models in the mandibular arch, but further research is nonetheless required in this field.

The effect of teeth extraction for orthodontic treatment on the upper airway: a systematic review

PURPOSE

The purpose of this study was to evaluate the effect of teeth extraction for orthodontic treatment on the upper airway.

METHODS

Relevant trials assessing the effect of orthodontic extractions on the upper airway were retrieved electronically through PubMed, Embase, Medline, Web of Knowledge, and the Cochrane Library. The processes of literature search, selection, quality assessment, and data extraction were performed by two authors independently.

RESULTS

Seven articles were included in this systematic review. They were categorized into three groups according to their indications for extractions, namely anteroposterior discrepancy (group 1), crowding (group 2), and unspecified indications (group 3). In group 1, enrolled patients were diagnosed with class I bimaxillary protrusion and had four first premolars extracted, with a significant decrease in upper airway dimension. In group 2, increase in the upper airway dimension was reported in patients who were diagnosed with class I crowding and four first premolars extracted. In group 3, all patients were adolescents and no significant change in the upper airway dimension was observed.

CONCLUSIONS

Currently, it is difficult to draw evidence-based conclusions because of the exceeding heterogeneity among included studies, and more qualified trials are required to provide reliable evidence. Extractions followed by large retraction of the anterior teeth in adult bimaxillary protrusion cases could possibly lead to narrowing of the upper airway. Mesial movement of the molars appeared to increase the posterior space for the tongue and enlarge the upper airway dimensions. Although the effect of teeth extraction on upper airway dimension seems to be related to indications for extraction, accepted scientific evidence is still insufficient owing to the limited number of included studies. The relationship between the upper airway size and the respiratory function has not been demonstrated. While there may be a decrease in the upper airway volume, there is no evidence that this would turn an airway more collapsible. None of the studies assessed in this review had actual functional assessment of breathing. Additional qualified trials are necessary to verify reliability.